Abstract
This study investigates the effect of dibenzothiophene on the hydrogenation of aromatic hydrocarbons over bifunctional catalysts based on mesoporous Al-HMS aluminosilicates. Mesoporous aluminosilicate materials with different Si/Al ratios varying from 10 to 70 were synthesized and employed as supports for Ni-Mo-Al-HMS-H-bentonite catalysts. The physico-chemical features of the materials were characterized using ICP-OES, nitrogen physisorption at low temperatures, XRD, FTIR, and pyridine adsorption FTIR spectroscopy. Catalytic activity was evaluated in the hydrogenation of a model mixture of 2-methylnaphthalene and n-hexadecane at temperatures between 220-300°C and at 6 MPa H2. The optimal catalytic performance was observed for the sample with a Si/Al ratio of 10, displaying high conversion and selectivity to 2-methyldecalin as a result of sufficient Brønsted and Lewis acidity. The presence of dibenzothiophene leads to a decrease in conversion and selectivity due to sulfur-induced catalyst poisoning and shifts the optimal reaction temperature from 240 to 260°C. These findings highlight the important role of acid properties of mesoporous aluminosilicates in hydrogenation and hydrotreatment processes of aromatic compounds.